Comment 12 for bug 1633545

I've experienced same problem. I assume problem is with some PPA applications running in python.

I tried @Lubos solution, but result was still same. I've noticed that after init 2 there was still running some proceses of my-weather-indicator. (PPA https://launchpad.net/my-weather-indicator ).
After I kill them I was able to finally run upgrade without errors.
sudo do-realease-upgrade
Unfortunatly upgrade stoped at installing python3-minimal package. After restart I was able to finish upgrade by
sudo apt-get install -f #to finish python3-minimal
sudo apt-get dist-upgrade #continue upgrade
Now it seems 16.10 upgrade is complete.